The invention pertains to quick-closing gates useful particularly in cattle handling operations, which are however also useful in numerous other applications as well.
In cattle shipping operations it is often necessary to move a number of cattle into a confined space, as for example into a cattle hauling truck or a railroad cattle car. As soon as the cattle have been herded into the truck or railroad cattle car it is necessary to close a gate to prevent egress of the cattle.
Since the cattle will naturally tend to be frightened by the operation of being herded into a closely confined space, and will quickly seize any opportunity to escape from such confinement, it is important that the operator be able to quickly close a secure gate, as soon as the cattle have been gathered into the desired confinement area. Otherwise there is a danger that a sudden outward movement of the cattle may result in serious injury to the operator, as well as escape of cattle.
Various types of gates or partitions for confinement of cattle are disclosed in the following United States patents known to applicant: Canda (U.S. Pat. No. 449,203; hereinafter "Canda '203"), Canda (U.S. Pat. No. 345,481; hereinafter "Canda '481"), and Hicks (U.S. Pat. No. 281,067). Also known to applicant is the patent of Fimbel (U.S. Pat. No. 2,966,212), which discloses wide vertically moving sectioned doors, and is not directly pertinent to consideration of applicant's invention, being mentioned only as indicating a background level of skill in the general art of movable gates and doors.
Canda '203 discloses gates for cattle cars, formed of linked bars or strips which move in ways (p. 1, lines 44-69). These gates have a chain and pulley mechanism (p. 1 line 70-p. 2, line 28) which functions to move the gates.
Canda '481 discloses gates for cattle cars, virtually identical to those disclosed in Canda '203, also using a chain and pulley mechanism to move the gates (p. 1, line 69-p. 2, line 18).
Hicks discloses movable partitions for cattle cars, comprised of bars moving in guide ways, which also are moved by a chain and pulley mechanism on either side of the car (p. 1 lines 21-69).
The Canda '203 patent teaches that the use of such chain and pulley mechanisms as disclosed in Canda '203, Canda '481 and Hicks, is conducive to fairly slow operation of such gates. The Canda '203 specification states that by the operation of the chain and pulley mechanism, "the gates may be prevented from sliding down with a rush when being lowered to divide the car into stalls or compartments" (p. 1, lines 70-74; emphasis added).
The Canda and Hicks patents do not disclose gates having a beneficial feature of applicant's gates, discussed below, namely gates in which the upper and lower portions of the tracks form an acute angle. Canda '203 discloses gates in which the upper portions of the tracks are inclined at an obtuse angle to the lower tracks (FIG. 2; p. 1 lines 60-69). Nor do these patents disclose gates in which the entire track assembly rotates about a pivot axis as in applicant's gate, allowing the upper track to easily and quickly move from a position in which gravity keeps the gate open, to a position in which gravity tends to close the gate.
Thus the patents discussed above disclose gates having a feature, avoided by applicant, conducive to slow operation of such gates, and lacking a feature of applicant's gates, conducive to quick closure of his gates.